1. Preheat oven to 350°F (175°C). Line a 9×13-inch pan with parchment paper.

2. In a bowl, melt 1 cup butter. Whisk in granulated sugar until smooth. Add eggs one at a time, then vanilla.

3. Sift in cocoa powder, flour, espresso powder (if using), and salt. Stir until just combined.

4. Pour batter into prepared pan and bake for 20–22 minutes. Center should be just set. Remove and let cool slightly.

5. Toast pecans in a dry skillet over medium heat for 5 minutes until fragrant. Roughly chop and set aside.

6. In a saucepan, combine brown sugar, corn syrup, heavy cream, and 4 tablespoons butter. Cook over medium heat until bubbling.

7. Remove from heat. Stir in vanilla, salt, and chopped pecans.

8. Pour pecan mixture over partially baked brownie layer. Spread evenly.

9. Return pan to oven and bake for 20–25 minutes until topping is bubbly and set.

10. Cool completely. For clean cuts, refrigerate for 1 hour before slicing. Serve at room temperature.